JP2005098521A - Synthetic resin cage and roller bearing for roller bearings - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure in which a continuous portion between each of the column portions 4, 4 and the annular portion 5 is not easily damaged even when a circumferential force is applied from the rollers 6, 6 to the column portions 4, 4.
Only the base end portions of the pillar portions 4 and 4 are connected to the annular portion 5, and the distal end portions are free ends that are not restrained. A connecting frame portion 8 extending in the circumferential direction is provided only between the tip portions of some of the column portions 4 and 4. Synthetic resin cage by connecting the connecting frame portion 8 to the end face of a part of the rollers 6 or by engaging a protrusion formed on a part of the pillars 4 and 4 with a part of the raceway. 1a is prevented from falling off.
[Selection] Figure 2

Description

The present invention relates for example spindle or the like of a machine tool, an improvement of the synthetic resin cage incorporating the roller bearing for supporting the rotating member to be operated while being lubricated with a high speed by the grease or lubricant traces.

  Bearings for rotatably supporting the spindle of a machine tool are required to have characteristics such as high rigidity, high rotational accuracy, and low heat generation in order to improve the machining accuracy. In recent years, in order to improve processing efficiency, high-speed stability is required so that it can be used stably for a long time at a high rotational speed. Of these characteristics, in order to improve the rigidity in the radial direction, a cylindrical roller bearing is often used as the bearing. In order to further improve the rigidity in the radial direction and improve the rotational accuracy, a so-called preload may be applied to make the internal gap of the cylindrical roller bearing negative. However, the application of such preload is a severe condition in which a rolling bearing such as a roller bearing is liable to cause a failure such as internal component wear or seizure. For this reason, in general rolling bearings for industrial machines, a positive gap is left in the bearing during operation so as to extend the peeling life and to suppress deterioration of the bearing function due to disturbance. In order to minimize heat generation during operation, rolling bearings for machine tools are often operated under lubrication conditions with a very small amount of grease or lubricating oil. That is, by suppressing the lubricant such as grease and lubricating oil to the minimum necessary, the stirring resistance of the lubricant and the heat generation based on the stirring resistance are suppressed.

  There are various problems to be solved in order to further increase the rotational speed of a rotating body such as a main shaft that is rotatably supported by a roller bearing under severe conditions as described above. As one of such problems, there is a problem of wear of a copper alloy cage that has been conventionally used for the roller bearing as a standard. In other words, when the roller bearing is used under the severe conditions as described above, both the inner and outer peripheral surfaces of the cage or the inner surface of the pocket are strong against the peripheral surface of the bearing ring and the surface (rolling surface and end surface) of the roller. rub against. For this reason, it is softer than hard metal such as bearing steel and the like constituting the bearing ring and the cage, and the cage made of copper alloy is worn, and wear powder is easily generated from the cage. In particular, when the roller bearing is lubricated with grease, the wear powder is mixed in the grease (contaminates the grease), so that the lubricity of the grease decreases. And when lubricity falls remarkably, the said roller bearing may receive damage, such as seizing and remarkable abrasion, in a short time.

  In view of such circumstances, in recent years, a cage made of a synthetic resin may be used as a cage incorporated in a roller bearing for rotatably supporting a rotating body that receives a large load such as a spindle of a machine tool. It is increasing. As a cage made of such a synthetic resin, a fiber reinforced synthetic resin in which an appropriate amount of a reinforcing material such as glass fiber is mixed in a synthetic resin having excellent friction characteristics (hard to wear) such as a polyamide resin is usually injected. The one made by molding is used. A roller bearing incorporating such a cage made of synthetic resin is less likely to generate wear powder even under the severe use conditions as described above, and can hardly cause damage such as seizure or significant wear.

  However, simply changing the material of the cage built into the roller bearing for rotatably supporting a rotating body that receives a large load, such as the spindle of a machine tool, from copper alloy to synthetic resin, the reliability of the rotating support part In addition, sufficient durability may not be ensured. The reason for this is as follows. That is, a synthetic resin material such as a glass fiber reinforced polyamide resin has smaller rigidity and breaking strength than a copper alloy. For this reason, it is difficult to ensure sufficient rigidity and strength with the same shape as the conventional copper alloy cage. For these reasons, the shape and dimensions of the synthetic resin cage are likely to be thicker and larger than conventional copper alloy cages.

In addition, in the case of a synthetic resin cage made of an axial draw type that can be made at low cost, the column part is displaced outward in the diameter direction based on the centrifugal force acting during operation, and both sides in the circumferential direction of these column parts However, there is a possibility of friction with the rolling surface. That is, if both sides in the circumferential direction of each column are cylindrical surfaces curved to the inner diameter side, and the width dimension of the pocket extending in the circumferential direction is narrower at the inner diameter side opening than the diametrically intermediate part, When each column portion is displaced outward in the diameter direction of the synthetic resin cage based on the centrifugal force acting at times, the circumferential side surfaces of the column portions and the rolling surfaces of the rollers are There is a possibility of strong friction.

In view of the circumstances as described above, the present invention is a structure that can be manufactured at a low cost by the axial draw type, and each column portion that is cantilevered on one side surface of the annular portion is formed on the basis of the centrifugal force acting during operation. Even if it is displaced outward in the diameter direction of the ring portion, it was invented to realize a synthetic resin cage in which the rolling surfaces on both sides in the circumferential direction of each pillar portion do not strongly rub against each other. is there.

Among the synthetic resin cages and roller bearings for roller bearings of the present invention, the synthetic resin cage for roller bearings described in claim 1 includes an annular portion disposed at one end in the axial direction and a circumferential direction. A plurality of pillars arranged at equal intervals and having one end continuous with the inner side surface of the annular part, both circumferential sides of each pillar part, and the inner side face of the annular part And a plurality of pockets for holding the rollers so as to roll freely. In particular, in the synthetic resin cage for roller bearings of the present invention, the circumferential side surfaces of the plurality of pillars include the curved surface portion of the outer circumferential portion of the annular portion and the flat portion of the radially inner portion. It is a smoothly continuous shape. Further, a pair of flat portions constituting the inner diameter side portion from the diametrically intermediate portion of both inner circumferential surfaces of the same pocket are parallel to each other. And the space | interval of a pair of curved surface parts which comprise the outer diameter side part of the circumferential direction both inner surface of the said same pocket becomes so narrow that it goes to the outer diameter side opening of each pocket.

In addition, the roller bearing described in claim 4 is an inner ring having a cylindrical inner ring raceway on the outer peripheral surface, and an outer ring having a cylindrical outer ring raceway on the inner peripheral surface, similarly to the conventionally known roller bearings. And a plurality of rollers provided between the two raceways so as to be capable of rolling, and a cage for holding the rollers so as to be capable of rolling. In particular, in the roller bearing of the present invention, the cage is a synthetic resin cage as described above.

According to the synthetic resin cage and roller bearing for the roller bearing of the present invention configured as described above, each pillar portion is cantilevered on one side of the annular portion with a structure that can be manufactured at low cost by the axial draw type. However, even when the annular portion is displaced in the diametrically outward direction due to the centrifugal force acting during operation, the rolling surfaces on both sides in the circumferential direction of the column portions do not rub strongly. .

1 and 2 show a first example of a reference example related to the present invention . The synthetic resin cage 1a of the present invention is made of a thermoplastic synthetic resin such as polyamide 66, polyamide 46, polyphenylene sulfide, polyacetal or the like as a base material, and about 10 to 30% by weight of glass fiber added for strength improvement. It is made by injection molding. However, depending on the use, when particularly sufficient elasticity is required for the synthetic resin cage 1a, it may be considered that an additive such as glass fiber is not added. The thermoplastic synthetic resin used as the base material is, in the case of a synthetic resin cage for a cylindrical roller bearing for supporting a main spindle for a general machine tool, in terms of cost, strength, chemical From the viewpoint of functional aspects such as mechanical stability, polyamide 66 is preferred. On the other hand, when the temperature conditions during normal operation or running-in operation become extremely severe (high temperature), or when better fatigue strength and rigidity are required, polyamide 46 has a high temperature, chemical resistance, humidity ( Polyphenylene sulfide is preferable when dimensional stability against moisture absorption is particularly required, and polyacetal is particularly preferable when abrasion resistance is particularly required.

In the case of the synthetic resin cage 1a of the present reference example , 27 column parts 4 and 4 arranged at equal intervals in the circumferential direction are provided as one piece arranged at one end part in the axial direction (left end part in FIG. 2). The annular portion 5 is supported in a cantilever manner. And in order to hold | maintain the roller 6 and 6 so that rolling is possible inside each part enclosed by three sides by the circumferential direction both sides | surfaces of each pillar part 4 and 4 and the inner surface of the said annular part 5 A plurality of pockets 7 and 7. And the other end parts (right end part of FIG. 2) of 3 sets 6 column parts 4 and 4 which exist in the circumferential direction equal intervals position are connected by the connection frame part 8 equivalent to a retaining piece. . The connecting frame portion 8 has a smaller cross-sectional area than the annular portion 5 and a bent shape in the circumferential direction to reduce rigidity in the circumferential direction. Further, in the illustrated example, the inner peripheral edge of the connecting frame portion 8 is positioned diametrically outward from the outer peripheral edge of the annular portion 5 so that the synthetic resin cage 1a can be made by an axial draw type. ing. Note that reducing the rigidity of the connecting frame portion 8 in the circumferential direction can be achieved by bending the shape instead of bending the shape extending in the circumferential direction or by bending the shape. It can also be dealt with by reducing the content of the reinforcing material such as glass fiber contained in the synthetic resin such as polyamide resin constituting 1a in the connecting frame portion 8 portion.

The synthetic resin cage 1a for roller bearings of the present reference example configured as described above is, for example, a single row cylindrical roller bearing 9, 9a, 9b as shown in FIGS. 3 to 5 or a double row cylinder as shown in FIG. It is incorporated in the roller bearing 10. As the machine tool or the like equipped with the single-row cylindrical roller bearing 9, 9a, 9b or the double-row cylindrical roller bearing 10 incorporating the synthetic resin cage 1a of this reference example is operated, the rollers 6, 6 become columns. Even if the portions 4 and 4 are strongly pressed, the stress generated in the synthetic resin cage 1a such as the connecting portion between the column portions 4 and 4 and the annular portion 5 does not become excessive.

  That is, as a result of the reason described above, the revolution speed of any one of the plurality of rollers 6 and 6 is different from the revolution speed of the other rollers 6 and 6. Even when a large force acting in the circumferential direction acts on the column 4 facing each other, the column 4 with one end supported in a cantilever manner on the annular portion 5 is displaced in the circumferential direction. Based on this displacement, it is possible to suppress an increase in stress inside the synthetic resin cage 1a, and to prevent the stress from becoming so large as to damage the synthetic resin cage 1a. As a result, even when the use conditions of the single row cylindrical roller bearings 9, 9a, 9b or the double row cylindrical roller bearing 10 vary and the assembled state is somewhat irregular, the single row cylindrical roller bearings 9, 9a, High-speed operation of a mechanical device having a rotation support portion such as a spindle of a machine tool incorporating the 9b or double row cylindrical roller bearing 10 can be stably performed for a long time. Further, even if a large force acting in the circumferential direction acts on the column part 4 whose other end is connected to the column part 4 adjacent by the connection frame part 8, the connection frame part 8 remains in the circumferential direction. By elastically deforming in a state of expanding and contracting, the force is absorbed and the stress is prevented from increasing.

Further, the connecting frame portions 8 provided at three positions in the circumferential direction prevent the synthetic resin cage 1a from being displaced in the axial direction with respect to the roller 6 based on the engagement with the end face of the roller 6. . Therefore, as shown in FIG. 5, the synthetic resin cage 1a of the present reference example has a single-row cylindrical roller bearing 9b that does not have a member facing the annular portion 5 of the synthetic resin cage 1a in the axial direction. Even when incorporated into the inner ring 11, the synthetic resin cage 1 a can be prevented from coming off in the axial direction from between the outer peripheral surface of the inner ring 11 a and the inner peripheral surface of the outer ring 12. The synthetic resin cage 1a of the present reference example has a flange 13 or a spacer facing the annular portion 5 of the synthetic resin cage 1a in the axial direction as shown in FIGS. In the case of incorporation in the single-row cylindrical roller bearings 9 and 9 having 14, the dimensions of each part are regulated as follows.

That is, in a state where one end surface of the roller 6 (left end surface in FIGS. 3 to 4) and one side surface of the annular portion 5 (right side surface in FIGS. The width of the gap Δ ₁ between the other end face of 6 (the interval between the annular portion 5 and the projection of the connecting frame portion 8 is L _7, and the length of the roller 6 is L _7. In the case of L ₆ , Δ ₁ = L ₇ −L ₆ ) is changed to the other side surface (the left side surface in FIGS. 3 to 4) of the annular portion 5 and the flange portion 13 (in the case of FIG. 3) or the spacer 14. greater than the gap width △ ₂ between the (case of FIG. _{4) (△ 1> △ 2} ) to. By regulating the widths Δ ₁ and Δ ₂ of these gaps in this way, the low-strength connecting frame portion 8 and the other end surface of the connecting portion 6 are prevented from rubbing, and the durability of the connecting frame portion 8 is ensured. Plan.

The strength of the entire synthetic resin cage 1a can be secured by the annular portion 5. Therefore, the strength of the synthetic resin cage 1a as a whole does not become insufficient as the column portion 4 is easily elastically deformed in the circumferential direction. On the other hand, for example, considering only the absorption of the force in the circumferential direction, one end portion and the other end portion of the plurality of column portions 4, 4 arranged at intervals in the circumferential direction. Even when alternately arranged in the circumferential direction, the force in the circumferential direction can be absorbed. However, when such a structure is adopted, the support rigidity of the pillars 4 and 4 in the diameter direction of the synthetic resin cage 1a is reduced, and the synthetic resin cage 1a rotates at high speed. In this case, each of the column parts 4 and 4 is relatively easily displaced outward in the diameter direction of the synthetic resin cage 1a, and the single-row cylindrical roller bearing 9, 9a, 9b or the double-row cylindrical roller bearing. The operating state of the rotating machine equipped with 10 becomes unstable. In the case of the structure of this reference example , since one end of each of the pillars 4 and 4 is continued to the annular part 5 that is continuous in the circumferential direction, such inconvenience does not occur.

Next, FIG. 7 shows a second example of a reference example related to the present invention . In the case of the synthetic resin cage 1b of this reference example , 28 column parts 4, 4 arranged at equal intervals in the circumferential direction are arranged at one end part in the axial direction (the back end part in FIG. 7). The individual annular portions 5 are supported in a cantilever manner. And the other end portions (front side end portions in FIG. 7) of the four sets of eight column portions 4 and 4 existing at equal circumferential positions are connected to each other by connecting frame portions 8 and 8 corresponding to retaining pieces. It is connected. In the case of the first example of the reference example described above, except that the number of the column parts is 28 which is a multiple of 4, and the connecting frame parts 8 and 8 are provided at four positions in the circumferential direction. It is the same. In addition, it is preferable to arrange | position the said connection frame parts 8 and 8 at equal intervals regarding the circumferential direction from the surface which ensures the rotational balance of a synthetic resin holder. However, when the rotational speed at the time of use is slow and it is not necessary to secure a high degree of rotational balance, or when the rotational balance can be ensured by slightly varying the weights of the connecting frame portions 8 and 8, It is not always necessary to arrange the connecting frame portions 8 and 8 at equal intervals in the circumferential direction.

Next, FIG. 8 shows a third example of the reference example related to the present invention . In the case of the synthetic resin cage 1c of the present reference example , a plurality of column portions 4 supported in a cantilever manner on the annular portion 5 with one end portion being continuous with one axial surface of the annular portion 5. Among them, a protruding piece 15 as a retaining piece is formed on the other end face of at least a part of the column part 4. The protrusion 15 engages the end face of the roller held in the pocket 7 is prevented from being displaced in the axial direction with respect to the synthetic resin cage 1c Gakoro. Even when the synthetic resin cage 1c of the present reference example is incorporated in a single row cylindrical roller bearing 9b as shown in FIG. 5, the synthetic resin cage 1c is provided with the outer circumferential surface of the inner ring 11a and the inner circumference of the outer ring 12. Prevents falling off from the surface in the axial direction. Other configurations and operations are the same as those of the first example of the reference example described above.

Next, FIGS. 9 to 10 show an embodiment of the present invention . The synthetic resin cage 1d of the present embodiment also has a plurality of column portions 4 arranged at equal intervals along the circumferential direction on one side surface of the annular portion 5 arranged at one end portion in the axial direction. The plurality of column portions 4 and 4 are supported by the annular portion 5 in a cantilever manner with one end portion of the four being continuous. And the roller 6 (FIG. 11) is hold | maintained so that the part enclosed by three sides by the circumferential direction both sides | surfaces of each pillar part 4 and 4 and the one side surface of the said ring part 5 can be rolled inside each. A plurality of pockets 7 and 7 are provided.

  In particular, in the case of the synthetic resin cage 1d for roller bearings of the present embodiment, a triangular shape is formed on the inner peripheral surface portion of at least some of the column portions 4, 4 among the plurality of column portions 4, 4. Engaging protrusions 16 and 16 are provided. These engaging protrusions 16 and 16 are formed when the above-mentioned synthetic resin cage 1d is incorporated in a single row cylindrical roller bearing 9b as shown in FIG. 11 or a double row cylindrical roller bearing 10 as shown in FIG. The synthetic resin retainer 1d is engaged with the inner surface of the flanges 17 and 17a formed on the outer peripheral surface of the inner rings 11a and 11b, and the outer peripheral surface of the inner rings 11a and 11b and the inner periphery of the outer rings 12 and 12a. Prevents falling off from the surface in the axial direction. Therefore, the diameter of the inscribed circle of the plurality of engaging protrusions 16 and 16 in the free state of the synthetic resin cage 1d is slightly smaller than the outer diameter of the flange portions 17 and 17a. Yes.

In the case of the present embodiment, of the engagement protrusions 16 and 16, the surface facing the flanges 17 and 17a formed on the outer peripheral surfaces of the inner rings 11a and 11b is the side surface of the flanges 17 and 17a. It is preferable to make the shape so that the grease adhering to the surface is not excessively scraped off. FIGS. 13 to 18 show three examples of shapes for preventing excessive scraping of such grease. First, in the first example shown in FIGS. 13 to 14, chamfers 18 and 18 are formed at both ends in the circumferential direction of the surface of the engagement protrusion 16 that faces the flanges 17 and 17 a. The second example shown in FIGS. 15 to 16 shows a part of the engaging projection 16 that has a part of the entire surface facing the flanges 17 and 17a as a partially cylindrical convex surface, as shown in FIGS. In the third example, the entire surface of the engaging protrusion 16 that faces the flanges 17 and 17a is an angled convex surface with a sharp central portion.

In addition, in the case of the Example of this invention shown in FIGS. 9-10, the circumferential direction both sides | surfaces of each said pillar part 4 and 4 are the curved-surface parts of the diameter direction outer side part of the said synthetic resin holder 1d. 19 and the flat portion 20 on the inner side in the diameter direction are formed in a smoothly continuous shape. Of these, the radius of curvature of the curved surface portion 19 is slightly larger (about 0.5 to 10%) than the radius of curvature of the rolling surface of the roller 6 to be held in the pocket 7. Further, a pair of flat portions 20, 20 constituting the inner diameter side portion from the diametrically intermediate portion of both inner circumferential surfaces of the same pocket 7 are parallel to each other. Further, the distance between the pair of curved surface portions 19, 19 constituting the outer diameter side portions of both inner surfaces in the circumferential direction of the same pocket 7 is made narrower toward the outer diameter side opening of the pocket 7. ing.

  By making the shape of both side surfaces in the circumferential direction of the pillars 4 and 4 as described above, the pillars 4 and 4 that are cantilevered on one side of the annular part 5 are operated. Even if the synthetic resin cage 1d is displaced outward in the diameter direction based on the centrifugal force acting at times, the circumferential side surfaces of the pillars 4 and 4 and the rolling surfaces of the rollers 6 are not affected. There is no strong friction. That is, the interval between the pair of flat portions 20 and 20 constituting the inner diameter side portions of both inner circumferential surfaces of the column portions 4 and 4 is such that the column portions 4 and 4 are diametrically outward. Even if it displaces, it does not narrow, and both side surfaces in the circumferential direction of the pillars 4 and 4 and the rolling surfaces of the rollers 6 do not rub strongly. On the other hand, both the circumferential side surfaces of the pillars 4 and 4 are cylindrical surfaces curved to the inner diameter side, and the width dimension of the pocket extending in the circumferential direction is narrower at the inner diameter side opening than the diametrically intermediate portion. Then, when each said pillar part 4 and 4 is displaced to the diameter direction outer side of the said synthetic resin holder 1d based on the centrifugal force which acts at the time of a driving | operation, the circle | round | yen of each said pillar part 4 and 4 is carried out. Since both sides of the circumferential direction and the rolling surface of the roller 6 may rub against each other, it is not preferable.

Further, the width W _{7 in} the circumferential direction of the outer diameter side opening of each pocket 7 is 0.7 to 0.9 times the diameter D ₆ (FIG. 11) of the roller 6 held in this pocket 7 {W _It is preferable to regulate in the range of ₇ = (0.7 to 0.9) D ₆ }. When the width W ₇ is wider than this (W ₇ > 0.9D ₆ ), the rollers 6 are located outside the pocket 7 when the interval between the adjacent column parts 4 and 4 is opened based on centrifugal force. There is a possibility that rolling of the roller 6 is inhibited by being caught in the opening on the radial side. Conversely, the width W ₇ narrower than this (W ₇ <0.7D ₆₎ The order, the thickness T ₄ of the synthetic resin cage 1d of over the diametrical direction the column sections 4, 4 Need to be increased. As a result, the inner peripheral surface of the outer ring 12, 12a constituting the roller bearing and the synthetic resin cage 1d are likely to interfere with each other, or the grease existing on the inner peripheral surface of the outer ring 12, 12a The outer peripheral edges of the column portions 4 and 4 are scraped off, causing problems such as poor lubrication between the outer ring raceway 6 and the rolling surface.

Furthermore, the chamfers 21 and 21 as shown in FIG. 19 are applied to the outer diameter side openings of the pockets 7 so that the grease adhering to the rolling surfaces of the rollers 6 at the outer diameter side openings is excessive. It is preferable not to scrape off. In order to achieve this object, the chamfering angle α of each of the chamfers 21 and 21 with respect to the diameter direction of the synthetic resin cage 1d is larger than 0 degree and smaller than the opening angle β of the outer diameter side opening. . More preferably, the chamfer angle α is set to be smaller than the opening angle β by 10 degrees or more (α ≦ β−10 degrees). Note that the opening angle β means that the curved surface portions 19 and 19 at the outer diameter side opening portions of the pockets 7 are assumed when the curved surface portions 19 and 19 are extended without changing the radius of curvature. And the angle of intersection between the center of each pocket 7 and the straight line passing through the center of the synthetic resin cage 1d. When the synthetic resin cage 1d satisfying the above conditions is incorporated in the single row cylindrical roller bearing 9b as shown in FIG. 11 or the double row cylindrical roller bearing 10 as shown in FIG. An appropriate gap Δ ₃ (see FIG. 11, for example, Δ ₃ ≈0.1 to 2 mm) is provided between each engaging protrusion 16 and the flange portions 17 and 17a. By giving such a modest gap △ _3, cylindrical roller bearing or subjected to vibration during operation, or even when the synthetic resin cage 1d is vibrated, can be maintained smooth operating condition.

Next, preferred shapes, dimensions, etc. when implementing the present invention will be described. First, the length of the column part 4 will be described.
As a result of experiments and analysis by the present inventor on the length of the column 4 provided in a cantilever manner on the synthetic resin cage 1d that is easily elastically deformed, it is found that there is an optimum range regarding this length. It was.
First, FIG. 20 shows a case where the length of the column part 4 is short. Further, FIG. 20 shows that the outer ring 12 and 12a, such as the single-row cylindrical roller bearing 9b shown in FIG. 11 or the double-row cylindrical roller bearing 10 shown in FIG. The stage in the middle of assembling the structure which has the flange parts 17 and 17a only on the outer peripheral surface of 11a and 11b is shown. At this stage, the plurality of rollers 6 and 6 are held on the outer peripheral surface of the inner ring 11a so as to be caught by the tip portions of the column parts 4 and 4 constituting the synthetic resin cage 1d. For this reason, when the length of each of the column portions 4 and 4 is short, the rollers 6 and 6 are easily dropped from the pockets 7 and 7 existing between the column portions 4 and 4 adjacent to each other in the circumferential direction.

In particular, the synthetic resin cage 1d is less rigid than a metal cage made of a copper alloy or the like. Therefore, as shown in FIGS. In the horizontal axis state in which the shafts are arranged in the horizontal direction, the column parts 4, 4 are easily bent due to the weight of the rollers 6, 6 held in the pockets 7, 7. The rollers 6 and 6 are easily detached from the pockets 7 and 7. According to the experiments and analysis conducted by the present inventors, when the synthetic resin cage 1d is used for a cylindrical roller bearing having a size of being incorporated into the rotation support portion of the spindle of the machine tool, When the length L 4 of each column part 4, ₄ is 50% or less of the axial length L ₆ of each roller 6, 6 (L ₄ ≦ 0.5 L ₆ ), the roller is in the middle of assembling the cylindrical roller bearing. 6 and 6 were found to be easily detached from the synthetic resin cage 1d.

On the other hand, the upper limit of the length L ₄ of the column sections 4, 4, rather than in terms of preventing the edge of such rollers 6,6 described above and restriction in terms of ensuring the stable operation of the cylindrical roller bearing There is a need. FIG. 22 shows a case where the length L 4 of each of the pillars 4 and ₄ is long. As shown in FIG. 22, when the column portion 4 becomes long, not only does the weight of the column portion 4 itself increase, but the center of gravity of the column portion 4 moves away from the annular portion 5 that is the support portion of the column portion 4. . For this reason, the centrifugal force applied to each column part 4 increases with the revolution movement of the synthetic resin cage 1d, and the deformation amount of the column part 4 based on the centrifugal force during high-speed operation is the length L ₄ . As it increases, it becomes larger in a quadratic curve. As a result, when the length L 4 of the column ₄ is large and the cylindrical roller bearing incorporating the synthetic resin cage 1d is operated at high speed, the column 4 has a diameter of the synthetic resin cage 1d. The outer peripheral edge of the columnar portion 4 interferes with the inner peripheral surface of the outer ring 12. Such interference is not preferable because not only the rotational resistance of the cylindrical roller bearing becomes large and unstable, but also the amount of heat generated during operation increases. Accordingly, it is advantageous that the length L 4 of each of the column parts 4 and ₄ is as short as possible from the viewpoint of ensuring stable operation of the cylindrical roller bearing.

In consideration of the above, in order to prevent the rollers 6 and 6 from falling off, and to prevent interference between the outer peripheral edge of the pillars 4 and 4 and the inner peripheral surface of the outer ring 12 during high speed operation, the length L ₄ of the pillar portions 4, 100% or less than 50% of the axial length L ₆ of the rollers _{6,6 (0.5L 6 <L 4 ≦} L 6), and more optimally, Fig. 23, it is desirable that the axial length L _{6 be about} 60 to 80% {L ₄ = (0.6 to 0.8) L ₆ } .

  24, two synthetic resin cages 1d and 1d are used for each row of rollers 6, and the lengths of the column portions 4 and 4 of these synthetic resin cages 1d and 1d are used. Considering the amount of axial movement of each of these synthetic resin cages 1d and 1d, it is possible to consider a structure in which the rollers 6 and 6 are not removed from these synthetic resin cages 1d and 1d as much as possible. . When such a structure is adopted, the lengths of the column parts 4 and 4 constituting the synthetic resin cages 1d and 1d are less than 50% of the axial length of the rollers 6 and 6, respectively. Preferably it is 30% or less. Thus, by using two synthetic resin cages 1d and 1d, the columns 4 and 4 have a diameter while preventing the rollers 6 and 6 from falling off from the respective synthetic resin cages 1d and 1d. It can be used at higher speeds with minimal deformation to the outside of the direction.

In the synthetic resin cage for roller bearings of the present invention, the base end portions of the column portions 4 and 4 are coupled to the annular portion 5, and the tip portions of the column portions 4 and 4 are separated from each other. Therefore, the lubrication conditions are improved. Accordingly, the cylindrical roller bearing incorporating the synthetic resin cage 1d of the present invention and the cylindrical roller bearing incorporating the conventional synthetic resin cage 1 as shown in FIG. A comparative experiment was performed. As a result of this experiment, the cylindrical roller bearing incorporating the synthetic resin cage 1d of the present invention achieves a significant increase in speed especially with a minute amount of lubrication, compared to the conventional cylindrical roller bearing incorporating the synthetic resin cage 1. I knew what I could do.

The experiment was conducted under the following conditions, and the rotational speed of the rotating shaft with the inner ring fitted and fixed was increased stepwise while confirming that the rotational speed reached an equilibrium state at each rotational speed. The rotation speed at which the temperature becomes unstable is set as the maximum allowable rotation speed.
Experimental conditions Cylindrical roller bearing used: N1014 (inner diameter 70 mm, 1/12 tapered hole, outer diameter 110 mm, width 20 mm, roller size: diameter 9 mm x length 9 mm)
Cage dimensions: 97 mm outer diameter, 87 mm inner diameter, 2.3 mm axial thickness of the annular part, 6.3 mm column length (70% of the axial length of the roller)
Cage Material: Polyamide 46 containing 30% glass fiber

  The structure of the test apparatus used for the experiment is shown in FIG. Of the plurality of rolling bearings for supporting the rotating shaft 23 in the housing 22, the uppermost rolling bearing is a single-row cylindrical roller bearing 9 as a test piece, and a small amount of lubrication is added to the single-row cylindrical roller bearing 9. Oil was supplied. The lubrication condition is oil-air lubrication in which oil air is ejected from the nozzle 24, and oil air containing VG32 turbine oil from the nozzle 24 toward the single-row cylindrical roller bearing 9 is set to a turbine oil capacity of 16 every 16 minutes. .01 cc was supplied. Such an experiment was performed by incorporating the cylindrical roller bearing incorporating the synthetic resin cage 1d of the present invention as shown in FIG. 23 and the conventional synthetic resin cage 1 as shown in FIG. This was done with a cylindrical roller bearing. The result is shown in FIG. In FIG. 26, the solid line α represents the experimental result of the cylindrical roller bearing incorporating the synthetic resin cage 1d of the present invention, and the broken line β represents the cylindrical roller bearing incorporating the conventional synthetic resin cage 1. The experimental results are shown respectively.

As is apparent from the experimental results shown in FIG. 26, the cylindrical roller bearing incorporating the synthetic resin cage 1d of the present invention is much faster than the conventional cylindrical roller bearing incorporating the synthetic resin cage 1. Can be achieved. This point will be discussed below.
Micro lubrication represented by oil-air lubrication and oil mist lubrication sprays rolling bearings in a state where a small amount of oil is mixed in a large amount of compressed air. For this reason, a small amount of lubricating oil must surely reach the inside of the rolling bearing, and the reached lubricating oil needs to be quickly discharged so as not to become the stirring resistance of the rolling bearing. The cylindrical roller bearing incorporating the synthetic resin cage, which is the subject of the present invention, is inferior in lubricating oil in and out compared to ball bearings. However, the synthetic resin cage 1d of the present invention has the pillars 4, 4. Are supported in a cantilevered manner with respect to the annular portion 5, so that the portions covering the rollers 6, 6 are each pillar portion 4, like the conventional synthetic resin cage 1. The both ends of 4 are less than those supported in a double-supported manner, and the oil entry / exit is increased. For this reason, it is considered that excellent temperature stability is exhibited particularly at high speed operation with a minute amount of lubrication.

  Through the experiments described above, the synthetic resin cage guided by the rollers 6 and 6 (both the inner and outer peripheral surfaces of the synthetic resin cage and the outer peripheral surface of the inner ring so as to be operated only in contact with the rollers 6 and 6). Even when the gap between the inner ring and the outer ring is sufficiently set), the annular part 5 is deformed into an elliptical shape during operation, and both the inner and outer peripheral surfaces of the annular part 5 are It has been found that there is a case where the inner ring outer peripheral surface or the outer ring inner peripheral surface may come into contact. In the case of a cylindrical roller bearing using a synthetic resin cage guided by the rollers 6 and 6, the outer peripheral surface portions of the flange portions 17 and 17 that are off the inner ring raceway on the outer peripheral surface of the inner ring are originally other Since it does not interfere with the parts, it usually does not give special considerations to the finished state, and may remain a turning surface or heat-treated surface with a large surface roughness. However, in this experiment, in the case of the synthetic resin cage 1d of the present invention in which only the base end portions of the pillar portions 4 and 4 are supported in a cantilever manner with respect to the annular portion 5, the rollers 6 and 6 Even in the case of the synthetic resin cage guided by the above, the outer peripheral surface of at least the flange portion 17 facing the inner peripheral surface of the annular portion 5 is ground, for example, of the flange portions 17, 17. It is preferable to improve the roughness. That is, by improving the surface roughness of this portion, even if the inner peripheral surface of the annular portion 5 and the outer peripheral surface of the flange portion 17 of the synthetic resin cage 1d interfere with each other, The frictional resistance of the abutting portion is small, and problems such as wear and heat generation can be prevented. In this case, if the surface roughness of the outer peripheral surface of the flange portion 17 is about 1S to 3S, it is preferable from the viewpoint of achieving both the wear prevention effect and the suppression of the cost increase.

  Next, the directionality of each column part 4 will be described with reference to FIGS. When these column portions 4 are made parallel to each other and perpendicular to the annular portion 5, as described with reference to FIG. 21, the column portions 4 are in contact with the roller during the assembly of the cylindrical roller bearing. When the roller 6 is elastically deformed by the weight of the roller 6, the rollers 6 are easily dropped from the pocket 7. Therefore, as shown in FIG. 27, if each of the column parts 4 is formed so as to incline in the direction toward the diametrically inward direction of the synthetic resin retainer 1d, the cylindrical roller bearing is being assembled. Even if each of the column portions 4 is elastically deformed due to the weight of the rollers 6, the rollers 6 are less likely to fall out of the pockets 7. Further, even when each of the column parts 4 is elastically deformed outward in the diameter direction of the synthetic resin cage 1d during high-speed rotation, the outer peripheral edge of each of the column parts 4 interferes with the inner peripheral surface of the outer ring 12. It becomes difficult to do.

  The inclination angle of each column portion 4 with respect to the central axis of the synthetic resin cage 1d (the amount of collapse of the column portion 4) in a state where no external force is applied is determined by the rotation of the curved surface portion 19 of each pocket portion 7 and each roller 6. This is equivalent to the amount of movement of the cage, which is the amount of movement of the synthetic resin cage 1d in the radial direction with respect to each of the rollers 6 in the assembled state of the cylindrical roller bearing due to the presence of a gap with the moving surface. It is preferable that the amount is slightly larger than the cage movement amount. If the amount of collapse of each column portion 4 is small, the effect of preventing the rollers 6 from falling off when the respective column portions 4 are elastically deformed by the weight of the rollers 6 cannot be obtained sufficiently. On the other hand, if the amount of tilting is too large, when the centrifugal force acting on each column portion 4 is limited, the tip of each column portion 4 restrains each roller 6 and the inside of the cylindrical roller bearing. Increases heat generation at

  If the falling amount of each column part 4 is set to the above-described appropriate value, the problem that the tip part of each column part 4 restrains each roller 6 is less likely to occur. When the cylindrical roller bearing is in a stopped state, a gap exists between the side surface near the base end of each column 4 and the rolling surface of each roller 6 as shown in FIG. As shown in FIG. 29, the side surface of the shift portion and the rolling surface of each roller 6 are close to or in contact with each other. In this way, as a result of the abutment side surfaces of the column portions 4 and 4 and the rolling surfaces of the rollers 6 abutting, the end portions of the column portions 4 and 4 slightly restrain the rollers 6. Even so, the end portions of the column portions 4 and 4 are separated from the rollers 6 by the elastic deformation of the column portions 4 and 4 due to the centrifugal force generated with the rotation of the cylindrical roller bearing. Therefore, when the maximum number of rotations is determined, the amount of tilting of each of the column parts 4 and 4 is calculated by taking the amount of movement of the cage and the amount of deformation into consideration, considering the amount of column deformation due to centrifugal force at the maximum speed. It can be set to the same level as the added one. When the amount of collapse of each of the column parts 4 and 4 is set in this way, the amount of elastic deformation of the column parts 4 and 4 based on the centrifugal force is small at a low speed. However, at the time of low speed, the friction speed between the tip portions of the column portions 4 and 4 and the rollers 6 is small, and the rollers 6 and the raceway surface are constrained. The amount of heat generated by the cylindrical roller bearing as a whole is smaller than that at the time of operation at the highest speed, and this is not a problem.

Next, preferred shapes of both the inner and outer peripheral surfaces of the column part 4 and the annular part 5 will be described. As in the present invention, in the case of the synthetic resin cage 1d in which only the base end portion of each pillar portion 4 is supported in a cantilever manner by the annular portion 5, the annular portion 5 has a cross-sectional area as large as possible. It is preferable to improve rigidity and strength. On the other hand, each of the column parts 4 has a cross-sectional area at the tip part so as to suppress elastic deformation based on centrifugal force with the joint part with the annular part 5 as a fulcrum and to enable higher speed operation. Is preferably as small as possible. In consideration of the above, it is preferable to adopt a shape as shown in FIG. 30 when implementing the synthetic resin cage 1d of the present invention. That is, concerning the outer diameter, the outer diameter of the annular portion 5 and D _5, the outer diameter of the distal end portion of the column sections 4 in case of the D _4, and D _5> D _4. On the other hand, regarding the inner diameter dimension, R ₅ <R ₄ where R ₅ is the inner diameter of the annular portion 5 and R ₄ is the inner diameter of the tip portion of each column portion 4. By restricting the dimensional relation of each part in this way, the rigidity and strength of the annular part 5 are ensured, and the outer peripheral edge of each column part 4 is not deformed due to centrifugal force during high speed operation. It is possible to make it difficult to interfere with the inner peripheral surface of the outer ring 12. In order to satisfy the relationship of D ₅ > D ₄ , the outer peripheral surface of each column portion 4 is inclined with respect to the central axis of the synthetic resin cage 1d. The inclination angle is about 2 to 4 degrees. Is appropriate. When setting the amount of collapse of each column part 4 described in FIG. 27 described above, the inclination angle of the outer peripheral surface of each column part 4 is the sum of the amount of collapse and the above 2-4 degrees. To do.

The side view which looked at the synthetic resin retainer of the 1st example of the reference example regarding this invention from the opposite side to the annular part. FIG. The half section sectional view showing the 1st example in the state where the synthetic resin cage of the 1st example of the reference example about the present invention was built in the single row cylindrical roller bearing. Sectional sectional drawing which shows the 2nd example. Half sectional view showing the third example The half section sectional view showing one example of the state where the synthetic resin cage of the 1st example of the reference example about the present invention was built in the double row cylindrical roller bearing. The side view which looked at the synthetic resin cage | basket of the 2nd example of the reference example regarding this invention from the opposite side to the annular part. The partial expansion perspective view which shows the synthetic resin holder | retainer of the 3rd example of the reference example regarding this invention. The fragmentary sectional view which shows the synthetic resin cage made of the Example of this invention. B arrow view of FIG. The half part sectional view which shows one example of the state which incorporated the synthetic resin cage of the Example of this invention in the single row cylindrical roller bearing. The half section sectional view showing one example of the state where the synthetic resin cage of the example of the present invention was built in the double row cylindrical roller bearing. The figure which looked at the synthetic resin retainer of the left side of FIG. 12 which showed the 1st example of the preferable shape of an engagement protrusion from the lower side of the same figure. The same figure seen from the right side. The figure which looked at the synthetic resin retainer of the left side of FIG. 12 which showed the 2nd example of the preferable shape of an engagement protrusion from the lower side of the same figure. The same figure seen from the right side. The figure which looked at the synthetic resin retainer of the left side of FIG. 12 which showed the 3rd example of the preferable shape of an engagement protrusion from the lower side of the same figure. The same figure seen from the right side. The figure similar to FIG. 10 which shows the preferable shape of the outer diameter side opening part of a pocket. Sectional drawing which shows the state in the middle of assembling a cylindrical roller bearing using the synthetic resin retainer which provided the short pillar part. The figure seen from the right side of FIG. The half part sectional view showing the state where this pillar part elastically deformed at the time of high-speed operation of the cylindrical roller bearing using the synthetic resin cage which has a long pillar part. The half part sectional view of the cylindrical roller bearing which uses the synthetic resin cage which provided the pillar part which has preferable length. Sectional drawing of the half part of the cylindrical roller bearing which uses two synthetic resin cages which provided the short pillar part. Sectional drawing of the experimental apparatus used in order to determine the quality of a lubrication state. The diagram which shows the result of the experiment conducted in order to determine the quality of a lubrication state. The half part sectional view of the cylindrical roller bearing which uses the synthetic resin cage which has the pillar part inclined in consideration of elastic deformation. CC sectional drawing of FIG. 27 for showing the relationship with the rolling surface of the side part of a pillar part. DD sectional drawing. Sectional drawing of the half part of a cylindrical roller bearing for showing the preferable shape of the inner and outer peripheral surfaces of the pillar part of a synthetic resin cage. The half part sectional view showing an example of the conventional synthetic resin cage for cylindrical roller bearings.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d Synthetic resin cage 2 1st ring part 3 2nd ring part 4 Pillar part 5 Ring part 6 Roller 7 Pocket 8 Connecting frame part 9, 9a, 9b Single row Cylindrical roller bearing 10 Double-row cylindrical roller bearing 11, 11a, 11b Inner ring 12, 12a Outer ring 13 Gutter part 14 Spacer 15 Projection piece 16 Engagement protrusion 17, 17a Gutter part 18 Chamfer 19 Curved part 20 Flat part 21 Chamfer 22 Housing 23 Rotating shaft 24 nozzles

Claims (2)

  An annular portion disposed at one end in the axial direction, a plurality of pillar portions disposed at equal intervals in the circumferential direction, and having one end continuous with the inner surface of the annular portion, and each of these A plurality of pockets provided on portions surrounded by three sides by both sides in the circumferential direction of the column part and the inner side surface of the annular part, and having a plurality of pockets for rolling the rollers inside each; A retaining piece is provided at the other end of at least some of the pillars to prevent the rollers existing in the pockets defined by the pillars from slipping out of the pockets in the axial direction. Synthetic resin cage for roller bearings.   An annular portion disposed at one end in the axial direction, a plurality of pillar portions disposed at equal intervals in the circumferential direction, and having one end continuous with the inner surface of the annular portion, and each of these For roller bearings provided with a plurality of pockets that are provided on the inner sides of the column part and surrounded by three sides by the inner side surface of the annular part, and that hold the rollers in a freely rolling manner. A synthetic resin cage, wherein the synthetic resin for a roller bearing is engaged with a part of a raceway ring constituting a roller bearing on a peripheral surface portion of at least a part of the plurality of column portions. A synthetic resin cage for roller bearings provided with a locking portion that prevents the cage made from being displaced at least toward one end with respect to the raceway.

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